Dual bend forming device and method

ABSTRACT

A sheet forming device and method capable of providing a hooked end on a sheet with one operation, the hook having a dual bend. The device incorporates a movable forming bar which enclamps the end portion of a sheet between the forming bar and a base. The forming bar has a radius bend lip projecting from it and a secondary angle die section spaced from the radius bend. The secondary angle die section overlies a urethane insert in the base. The urethane is displaced by the pressure of the forming bar against the plate sufficient to force the plate to conform with the die surface of the forming bar. A folding bar is actuatable to bend the end of the plate around the radius bend.

United States Patent 11 1 Kaufmann et al.

Dec. 11, 1973 DUAL BEND FORMING DEVICE AND [54] 1,029,012 6/1912 Higgin 72/321 METHOD FOREIGN PATENTS OR APPLICATIONS Inventors: HaroldKaufmnnn, Rochester; 204,365 11/1956 Australia 72/57 Edward S. Lavoy, Lake City, both of Primary Examiner-Lowell A. Larson 731 Assignee: Houdaille Industries, Inc., Buffalo, Sherman NY. [57] ABSTRACT 2 Fl d: 0 7 2] l e 2 l9 2 A sheet forming device and method capable of provid- [21 Appl. No.: 236,025 ing a hooked end on a sheet with one operation, the hook having a dual bend. The device incorporates a 52 U. c1 72 57 72 2, 4 mvab1e fmmmg bar whch endamps the end E J Cl 2 2 ,3? of a sheet between the forming bar and a base. The [58] Field 320 321 forming bar has a radius bend lip projecting from it and a secondary angle die section spaced from the radius bend. The secondary angle diie section overlies a he urethane is dis laced [56] References Clted urethane Insert 1n the base p by the pressure of the forming bar against the plate UNITED STATES PATENTS sufficient to force the plate to conform with the die 3,187,542 Heller urface of the forming bar A bar is actuatable to bend the end of the plate around the radius bend.

3:276:239 10/1966 Achler et- 72/465 4 Claims, 5 Drawing Figures I 3371.529 MENIEMEB 1 1 ms 1 DUAL BEND FORMING DEVICE AND METHOD BACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to forming devices and methods, more particularly to asheet material bending ap paratus and method capable of providing multiple bends substantially simultaneously in one operation.

2. Prior Art In forming metal, particularly in forming sheet metal, itis often-times desirable to provide two closely spaced bends. Numerous machines have been devised for bending sheet metal, incudingdevices capableof forming hook ends on the end of asheet. Specific industries, such as by way of example, the printing industry, have requirements for hooked end sheets. Printing plates are a specific example of such hook-ended sheet metal devices, the hookedend being used in attaching the plate to the press. However, such hooked ends require not only the formationof a hook on the end of the sheet metal, but the formation of a secondary bend closely spaced from the hook 'whichangles thesheet in the direction of the hooked projection.

I-Ieretofore, machines have been provided which form the hook end by bending the sheet metal around a radius bend die. It has, however, been necessary to perform asecondary die operation on the sheetmetal to provide the secondary angle or bend. This has, at

times, required the use of separate forming presses or machinesor the constructionof a complex machine capable of performing both bends in primary and secondary operations. In those instances where the same machine has been constructed to provide both bends in primary and secondary operations, it has been necessary to provide separatelymovableforming members ordies for the formation of the secondary bend. It would be an advance in thestateof the artif a method could be provided for forming both the hook end and the secondary bend simultaneously or, at the least, without requiring alarge number of moving parts such as moving dies.

SUMMARY The invention provides a method anda device capable offorming adouble-angled hook end on sheet material ina minimum number of steps. The sheet material is first enclamped between a forming bar having a radius bend projection and then it is subjectedto a radius brake orfolding bar which moves the end of 1the sheetmetal around the radius bend of the forming bar. Thesecondary angle is formed without any additional steps being necessary by the provision of a urethane insertreceived in a channel ina base member underlying the enclamping forming bar. As the bar descends to enclampthe sheet metal, it presses the sheet metal against the urethane block deforming the urethanecBecause of the peculiar properties of urethane rubber, including its substantial incompressibility and extreme resilience, ,it willactas a confined hydraulic fluid to deformto fill the channel in which it is received-while exerting substantially uniform pressure simultaneously atall of its surfaces. The pressure exerted by the top surface of the urethane rubber againstthesheet material enclamped between the rubber and the descending forming bar will force thesheetmaterialto conform to the shape of the undersurface of the forming bar. Therefore, by providing. an angled face on the undersurface of the forming bar, the same operation which enclamps the sheet material will cause the urethane to form the sheet matesheet material by movement of a radius brake or moving folding bar, which will move a projecting portion of the end of the sheet metal around a radius bend shoe or projection on the formingbar.

In the preferred embodiment illustrated, the urethane block is received in a rectangular channel in the base member of the machine. However, the urethane block has a non-rectangular configuration in its free statelwith a top surface projecting above the surface of the base and a bottom surface chamfered to leave a bottom portion of the channel unfilled.

It is therefore anobject of this invention to provide a method-and apparatus for forming sheet metal.

It is a further object of this invention to provide a method and apparatus for forming a hook end with the end projecting at an angle on a strip of sheet material.

It is a more specific object of this invention to provide a sheet metal forming device capable of forming a hook end on a strip of sheet metal, the hook having a radius bend end portion and a secondary bend spaced from the radius bend.

It is a more specific object of this invention to provide a sheet metal forming device which forms a bend in a strip of sheet metal by pressing the sheet metal against a urethane block by a forming bar having an an- It is a general object of this invention to provide a simplified one-step method of forming a double bend hook end on a strip of bendable sheet material.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects, features and advantages of the invention will be readily apparent from the following description of a preferred embodiment thereof, takenin conjunction with the accompanying drawings, although variations and modifications may be effected without departingfrom the spirit and scope of the novel con-. .cepts of the disclosure, and in which:

FIG. I is a diagrammatic plan view of a formingmachine according to thisinvention, illustrating the machine in open and (by dotted lines) closed positions.

FIG. 2 is a fragmentary cross sectional view of the sheet metal hooked end formed by the device of FIG. 1.

FIG. 3 is a fragmentary enlarged side view .of the metal forming end of the forming bar of the device of this invention.

FIG. 4is an enlarged fragmentary view of thermetal formingsection of the base of the device of, FIG. 1.

FIG. 5 is anenlarged view similarto FIG. 4, showing the position of the forming bar during the metalbendingoperationandillustrating the formation of the secondary angle.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 2 illustrates the end portion of a strip of sheet metal 11 such as is used in printing plates. The end has a hook 12 formed at the terminus thereof, as a radius bend in the metal. Closely spaced to the hook is a secondary bend 13.

The prior art has normally produced the hook 12 by enclamping the sheet metal 11 in a device which thereafter bends the end ofthe metal to form the hook. Subsequent operations were then provided to create the secondary bend 13. It is a primary object of this invention to provide a device which will utilize the closing force of the member which enclamps the sheet metal for the formation of the hook end to form the secondary angle 13 by pressing the sheet metal against a urethane block by a surface which has a corresponding angle formed thereon.

The method of forming the dual bend hooked end according to this invention then incorporates only the steps of enclamping the sheet material between a first surface and the undersurface of a radius bend ended forming bar and a second step of bending an end portion of the sheet material around the radius bend end of the forming bar. Thus, the method is essentially a one-step forming process wherein the only bending step comprises bending the end of the sheet material around the radius bend end of the forming bar. However, the method incorporates an initiating step of enclamping the sheet material and due to the presence of the urethane rubber insert in the first surface, the secondary bend is formed simultaneously with the enclamping step as the urethane rubber forces the sheet to conform to the undersurface of the forming bar, the undersurface having an angle.

FIG. 1 illustrates a device which uses this method for forming the sheet metal end portion 10 in the manner described. The device includes a machine base 18 having a top surface 19 above which is suspended a forming arm 20 or movable-shoe. The arm 20 is pivotably attached as at 21 to the base 18 and is driven by a connecting arm 22 which is attached through a cam pivot 23 to a handle 24. Operation of the handle 24 from the position illustrated at 25 to the position illustrated at 26 moves the connecting arm 22 downward in an are from a point 29 above the arm pivot center point 23 to a point 30 therebelow. The connecting arm 22 is pivotally attached to the forming bar or movable shoe 20 and therefore moves the shoe from the position illustrated at 32 to the position shown by the dotted lines 33. This brings the metal forming end 35 of the forming bar to the surface 19 of the base 18. A strip of sheet metal 38 received through a central opening in the forming bar with its end projecting to a point 39 beyond the forming end 35 will be enclamped between the forming end 35 and the base surface 19.

An end portion 39 of the sheet material extends beyond the end 40 of the surface 10 and overlies a folding bar 41 which initially has a top surface 42 on a plane with the surface 19 of the base 18.

The folding bar 41 is attached to a handle 43 and is pivotably mounted to the base 18 for arcuate movement around a pivot point 44. Movement of the handle 43 from the position illustrated at 45 to the position illustrated at 46 moves the folding bar from the position illustrated at 47 to the position illustrated at 48. This curles the end portion 39 of the sheet metal 38 around the end of the forming bar 35.

As best illustrated in FIG. 3, the end portion 35 of the forming bar 20 has a radius bend projection 49 extending therefrom. The radius bend projection has an outer surface which conforms to the inner surface 50 of the hook 12 formed in the sheet metal as illustrated in FIG. 2. Therefore, when the sheet metal end 35 is curled around the radius bend end of the forming bar, the metal will be bent to be curled or hook end configuration illustrated in FIG. 2.

Spaced from the radius bend projection 49 on the bottom side 51 of the end 35 of the forming bar is an angle 52. The undersurface of the end 35 projects away from the angle 52 as at 53. The angle bend 52 is used to form the secondary angle 13 of the hook end of FIG. 2.

The base member 18 has a groove 60 extending thereinto from the surface 19 inan area immediately below the end portion 35 of the forming bar when the forming bar is in the position illustrated at 33. The

groove underlies the angle bend 52 of the end portion 5. The groove 50 has a ure- 35 as illustrated in FIG. thane rubber block 62 received therein as illustrated in FIGS. 4 and 4.

The urethane rubber block preferably has an area substantially equal to or greater than the area of the groove 60. Further, the urethane block 62 preferably has a top surface 64 configuration which projects at least a portion 65 of the urethane block 62 above the surface 19 of the base. As will be evident from an examination of FIGS. 4 and 5 in the embodiment illustrated, the urethane block 62 has a peaked surface 64, the peak 65 being disposed in an area immediately behind the angle 52 of the end 35 of the forming bar when the forming bar is in its lowest position enclamping the sheet metal strip 38 between the surface 19 of the base 18 at the point 65 beyond the groove 62 and the bottom or undersurface 51 of the forming block. By placing the peak 65 slightly to the rear of the angle 52 as illustrated, the urethane is preformed in a manner which will aid in pressing the sheet against the undersurface of the forming bar to form the angle 13.

In order to allow movement of the urethane, a bottom corner 68 is chamfered as at 69 so as to not completely fill the bottom of the groove 60.

In operation, a sheet of material 38 has an end portion 39 inserted into the central opening 70 as illustrated in FIG. 1, with the end portion 39 projecting beyond the front end 40 of the base 18 and overlying a portion of the forming bar 41. Thereafter, the handle 24 is moved from the position 25 tothe position 26 moving the forming bar 20 from the position illustrated at 33. This brings the end portion 35 of the forming bar down to enclamp the end 39 of the sheet material between the land 65 spaced between the end 40 of the base and the groove 60. Alignment pins 72 are provided on the land 65 to index with bores 73 in the end portion 35 of the forming bar. The enclampment of the sheet metal also forces the sheet metal against the urethane block 62 toward the front edge 75 of the groove 60. This forcing of the sheet metal against the urethane causes the urethane to flow. Because of the incompressibilty of the urethane, it will force the sheet, in the area above the groove, against the undersurface 51-53 of the end 35 of the forming bar. This will cause the sheet metal to be bent against the angle 52 to conform to the angle, thereby providing the secondary angle 13 of the hooked end 10.

Thereafter, the handle 43 is moved from the position 45 to the position 46, moving the forming bar from the position illustrated at 78 in FIG. 5 to the position illustrated at 79 in FIG. 5. This curls the end portion 39 of the sheet metal which initially overlies the end of the forming bar 41 around the radius bend end 49 of the forming bar to form the hooked end of FIG. 2.

It can therefore be seen from the above that our invention provides a device capable of substantially similtaneously forming a hooked end and a secondary angle spaced from the hooked end in the end of a strip of sheet material without the necessity of secondary apparatus or secondary steps to form the secondary angle. The secondary angle is formed in the same step which enclamps the end of the sheet material for formation of the hook by pressing the sheet material against a urethane block which will in turn urge the sheet material against an angled face on the forming bar used to enclamp the sheet material.

Although the teachings of our invention have herein been discussed with reference to specific theories and embodiments and although illustrative means for accomplishing explained results have been described, it is to be understood that these are by way of illustration only and that others may wish to utilize our invention in different designs or applications.

We claim as our invention:

1. A device for forming a hook end for sheet material with a secondary bend closely spaced to the hook end comprising a base member having a top surface with an end face, a forming bar positioned above said top surface, said forming bar movable from a position above said top surface to a second position closely spaced to said top surface, said forming bar having a projection terminating in a radius bend, said projection overlying a portion of said top surface and extending beyond said end face when in said second position, said forming bar having a bottom surface with a first portion including a portion of said projection, a second portion of said bottom surface projecting at an angle to the first portion, the juncture of the first and second portions overlying a second portion of the top surface, means for inserting an end portion of a strip of sheet material be tween-said top surface and said bottom surface with a portion extending beyond the said end face, means for bending the said portion of the sheet material extending beyond the said end face around the said radius bend projection of the said forming bar and means forcing a portion of the said sheet material against the juncture between the first portion and second portion of the bottom surface of the forming plate to conform the sheet material to said angle the means for forming including a groove in the second portion of the top surface with a mass of urethane rubber in the groove having an area sufficient to force part of the sheet material into conformity with the angle at the juncture when the forming bar is in its second position.

2. The method of forming a hooked end on a strip of sheet material with a secondary angled bend spaced from the hook usinga forming bar having a radius bend projection and an angled undersurface which comprises the steps of: providing a surface having a channel therein, providing a mass of urethane rubber in the channel having an area greater then the channel, enclamping the end portion of a sheet material between the surface and the forming bar with the angle of the forming bar overlying the channel by moving the forming bar towards the channel, pressing the forming bar against the sheet material and the sheet material against the urethane rubber, flowing the urethane rubber to fill the channel and to pressure the sheet material against the angled surface of the forming bar and bending the end of the sheet material around the radius bend projection, and withdrawing the forming bar.

3. The device of claim 1 wherein the urethane rubber has a free configuration with a top surface having a portion thereof lying above the top surface of the base member.

4. The device of claim 3, wherein the urethane rubber has a peaked top surface, the peak positioned behind the junction of the first and second portions of the bottom surface of the forming bar when the forming bar is in its second position.

UNETEE 5mm 1mm QFFKCE CERTKFHCATEGP? CQRRECTION fl atentNo. 3,777,529 Dated December 11, 1973 e (s) r Kaufmann et 31 It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 33 01" Wncuc'iiiig" read ---inc1u6ling---Y." I Coluriin 3, line 59 for "16 -19" I Cblumn 4, line 23, i0? "50" read -60 0 Column 4, line 25, for "4 and 4" read "4 and 5--. Column 4, line 54 fszc #33 should read 32 to Hie posi gi qn illustrated to 336;

Signd and. sealed of October 1974,

3 (SEAL) Attest:

MCCOY M. GIBSON JR. c. MARSHALL DANN Attesting Officer Commissioner of Patents j PC4050 9 USCOMM-DC 003104 01 a: U. 5. GOVERNMENT PRINTING OFFIC! "l9 O-3GG'JJ4, 

1. A device for forming a hook end for sheet material with a secondary bend closely spaced to the hook end comprising a base member having a top surface with an end face, a forming bar positioned above said top surface, said forming bar movable from a position above said top surface to a second position closely spaced to said top surface, said forming bar having a projection terminating in a radius bend, said projection overlying a portion of said top surface and extending beyond said end face when in said second position, said forming bar having a bottom surface with a first portion including a portion of said projection, a second portion of said bottom surface projecting at an angle to the first portion, the juncture of the first and second portions overlying a second portion of the top surface, means for inserting an end portion of a strip of sheet material between said top surface and said bottom surface with a portion extending beyond the said end face, means for bending the said portion of the sheet material extending beyond the said end face around the said radius bend projection of the said forming bar and means forcing a portion of the said sheet material against the juncture between the first portion and second portion of the bottom surface of the forming plate to conform the sheet material to said angle the means for forming including a groove in the second portion of the top surface with a mass of urethane rubber in the groove having an area sufficient to force part of the sheet material into conformity with the angle at the juncture when the forming bar is in its second position.
 2. The method of forming a hooked end on a strip of sheet material with a secondary angled bend spaced from the hook using a forming bar having a radius bend projection and an angled undersurface which comprises the steps of: providing a surface having a channel therein, providing a mass of urethane rubber in the channel having an area greater then the channel, enclamping the end portion of a sheet material between the surface and the forming bar with the angle of the forming bar overlying the channel by moving the forming bar towards the channel, pressing the forming bar against the sheet material and the sheet material against the urethane rubber, flowing the urethane rubber to fill the channel and to pressure the sheet material against the angled surface of the forming bar and bending the end of the sheet material around the radius bend projection, and withdrawing the forming bar.
 3. The device of claim 1 wherein the urethane rubber has a free configuration with a top surface having a portion thereof lying above the top surface of the base member.
 4. The device of claim 3, wherein the urethane rubber has a peaked top surface, the peak positioned behind the junction of the first and second portions of the bottom surface of the forming bar when the forming bar is in its second position. 